The goals of my fellowship training are to: 1) gain increased knowledge and familiarity regarding psychosocial function and cognitive development related to aging; 2) obtain additional training in advanced behavioral genetic statistics and longitudinal analysis; 3) gain hands-on experience in data collection in longitudinal studies of aging and 4) examine the complex relationships among, cognitive, physical and psychosocial function using both the twin design and a nationally representative longitudinal aging sample. Aim 1 seeks to understand the joint influence of physical and psychosocial function on later-life cognition, utilizing data from the National Social Life, Health and Aging Project), a nationally representative, study of > 3,000 community-dwelling older adults. My proposed project will focus on cognitive aging by examining how the interaction of physical and psychosocial factors, and change in these factors, affect cognitive outcomes. Physical function measures include blood pressure, body mass index, and medication. NHSAP contains extensive psychosocial measures, including anxiety, self-esteem, perceived stress, and social networks. Aim 2 will examine how physical function and psychosocial characteristics affect genetic and environmental influences underlying individual differences in cognitive function in middle age. Aim 2 will use data from the Vietnam-Era Twin Study of Aging (VETSA), an ongoing, NIH-funded study of a nationally representative cohort of middle-aged male twins. My proposed project will focus on measures of grip strength, pulmonary function, body mass index, gait, blood pressure, and medication use as indices of physical function, and on self-reports of coping, self-esteem, social support, stress reaction and life events, as measures of psychosocial characteristics. A strength of VETSA is its extensive cognitive assessment including measures representing multiple cognitive domains. In addition, Wave 1 of the VETSA obtained baseline assessment of middle-aged men within the narrow age window of 51-60 years. This novel feature of VETSA allows us to study individuals just prior to many observed age-related changes in health and cognition. VETSA also utilizes the twin design, a powerful tool for under-standing the complex interplay of genetic and environmental factors on aging phenotypes. This proposal will examine whether the relative importance of genes and environments on individual differences in cognition varies across different physical and psychosocial health profiles (e.g. GxE interaction). The results of this project will lead to a better understanding of the complex influences and predictive value of physical and psychosocial function on later-life cognition and of the genetic underpinnings of the interrelations among physical, psychosocial, and cognitive function in midlife. Because both physical and psychosocial function are both amenable to intervention, it is important to research the potential impact(s) of physical and psychosocial factors on cognition, perhaps leading to cheaper behavioral strategies to prevent and improve age-related cognitive deficits.